Field of the Disclosure
The present disclosure, for example, relates to wireless communication systems, and more particularly to channel feedback design and scheduling for non-orthogonal and/or frequency selective channels in a wireless communication system.
Description of Related Art
Wireless communication systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include code-division multiple access (CDMA) systems, time-division multiple access (TDMA) systems, frequency-division multiple access (FDMA) systems, and orthogonal frequency-division multiple access (OFDMA) systems.
By way of example, a wireless multiple-access communication system may include a number of base stations, each simultaneously supporting communication for multiple communication devices, otherwise known as user equipments (UEs). A base station may communicate with UEs on downlink channels (e.g., for transmissions from a base station to a UE) and uplink channels (e.g., for transmissions from a UE to a base station).
Communication systems may take advantage of multiple antenna techniques for increased reliability or capacity. Multiple antenna techniques include transmit diversity and multiple-input multiple output (MIMO) techniques. MIMO systems that employ NT transmit antennas and NR receive antennas may realize a capacity increase of min{NT, NR} over single antenna techniques. Another approach that may be used in certain situations includes the transmission of non-orthogonal downlink signals over the same resources to multiple users. However, in a multiple access system, the possible variations in techniques including single-user MIMO (SU-MIMO), multiple-user MIMO (MU-MIMO), and/or non-orthogonal multiple access (NOMA) can provide challenges in optimizing scheduling for multiple downlink transmissions to multiple UEs.